Midfield man Allen, 23, has failed to nail down a regular first-team spot at the Anfield giants since moving from Swansea 18 months ago – and has started just seven Premier League games this term.

But Goodison boss Martinez, who gave Allen his Swansea debut as a teenager, remains a firm admirer of the Wales international and has discussed him as a summer transfer target for the Toffees.

Martinez is likely to have a midfield vacancy unless Gareth Barry’s loan move from Manchester City can be made permanent.

And Liverpool may be willing to sell Allen this summer, although they paid £15million for a player who will still have three years left on his contract at the end of the season.

So, Allen is unlikely to come cheap and Everton would need to pay upwards of £10m – making him the most expensive signing Everton have ever made from their rivals across Stanley Park.

After his apprenticeship at Swansea, Allen fits in perfectly with Martinez’s preferred style of possession football.

But Jordan Henderson has moved ahead of him in the Liverpool pecking order, so Brendan Rodgers would be unlikely to stand in the way of the player getting regular first-team football elsewhere, if the price is right.

It’s 22 years since Everton last bought a player from Liverpool, a £750,000 deal for defender Gary Ablett, so the historic nature of any Allen transfer can’t be underestimated.